Going out on your own
How to start a plumbing business in Ontario
Plumbing is a compulsory trade in Ontario. You need a 306A Plumber Certificate of Qualification to do the work, and many municipalities additionally require a Master Plumber licence to pull plumbing permits.
Plumbing at a glance
- Licence to do the work
- Required — 306A C of Q (compulsory); municipal Master Plumber licence to pull permits
- Path in
- Apprenticeship — about 9,000 hours (5 years)
- Regulated by
- Skilled Trades Ontario + your municipality (+ TSSA for gas)
- Insurance baseline
- $2M CGL — confirm water-escape coverage
- Union route
- UA locals
Plumbing is a compulsory trade in Ontario. You cannot legally do this work, or hire people to, without the required certification. This is the key difference from non-compulsory trades and the first thing to sort out.
The steps to start your plumbing business
- 1
Incorporate your company
Most contractors incorporate (Ontario or federal) to limit personal liability, look credible to larger clients, and access tax advantages once profitable. You choose a named or numbered company, set directors and share structure, and file the articles. Budget roughly $400–$600.
Full guide: Incorporation - 2
Register your CRA accounts
Get a Business Number, then register for HST/GST (mandatory once you exceed $30,000 in revenue, and worth registering sooner to claim input tax credits), a payroll account if you will hire, and corporate income tax. This is free and done through the CRA.
Full guide: CRA Registration - 3
Register for WSIB
Construction is a mandatory WSIB sector. Independent operators and partners in construction generally must register even with no employees, and clients and general contractors will require a valid WSIB clearance certificate before letting you on site.
Full guide: WSIB & Provincial - 4
Get certified and licensed for plumbing
Plumbing work requires a 306A Plumber Certificate of Qualification (a compulsory trade), or apprentice status under a certified plumber. To pull plumbing permits, many municipalities (e.g., Toronto) require a municipal Master Plumber/Plumbing Contractor licence. Backflow prevention work needs separate certification, and any gas-appliance connections require a TSSA gas fitter ticket.
Full guide: Trade Licensing - 5
Get insured
Carry Commercial General Liability (typically $2M, $5M for commercial/industrial work), plus tools and equipment, commercial auto, and — depending on scope — builders risk and professional liability. Many contracts and clients specify minimum coverage before you can quote.
Full guide: Insurance - 6
Set up health, safety & compliance
Meet your Occupational Health and Safety Act duties: a health and safety policy, required training (WHMIS, Working at Heights where applicable), and — for commercial and public work — often COR® certification. This is also where any trade-specific safety tickets live.
Full guide: Safety Compliance - 7
Stand up your operations
Open business banking, set up construction-specific accounting, and understand your trust obligations under the Construction Act (holdback, prompt payment, and adjudication). This is the back office that keeps you paid and out of trouble.
Full guide: Operational Setup - 8
Get bid-ready and win work
Assemble your prequalification package — incorporation and WSIB documents, insurance and bonding letters, safety program, key personnel, and project references — then quote, send proposals, and collect on invoices. This is where a construction business actually makes money.
Full guide: Bid Readiness
Insurance for a plumbing business
Water is the most common source of property-damage claims in construction. Carry at least $2M CGL, and confirm coverage for water escape and "resultant damage" — a small leak can cause six-figure damage in a finished building.
Your launch checklist
The whole page in one list. Screenshot it, stick it on the dash of the truck.
- Incorporate your company
- Register your CRA accounts
- Register for WSIB
- Get certified and licensed for plumbing
- Get insured
- Set up health, safety & compliance
- Stand up your operations
- Get bid-ready and win work
Plumbing questions, answered
Do you need a licence? How much does it cost? See the FAQs.
Plumbing overview
Licensing, regulators, and certifications at a glance.
Skip the paperwork. Let AEC Stack set it up
AEC Stack runs the whole process for a plumbing business: incorporation, CRA, WSIB, trade licensing, insurance, compliance, and the operations to win your first contract.
Start your plumbing business